The German market leader paid 2.2 billion euros for 5G spectrum at a recent auction and the regulator has just unlocked access to the 3.6 Gigahertz band that will power its initial 5G offering.
Berlin, Munich, Cologne, Bonn and Darmstadt now offer local 5G services with bandwidth of up to 1 gigabit per second - fast enough to download a movie onto a smartphone in a few seconds.
Hamburg and Leipzig will follow by the end of the year, with 20 German cities to be covered through 2020, Deutsche Telekom said in a statement.
"We are bringing 5G to the streets and will orient ourselves towards our customers' needs," Telekom's chief technology officer Walter Goldenits said. "We will go where the demand for data is greatest."
Rival Vodafone has also announced its 5G rollout in Germany and is challenging Deutsche Telekom on price.
IFA, the world's biggest consumer electronics fair, is being held as smartphone suppliers and makers hope 5G will give them a boost as they face a decline in sales this year amid U.S.-China trade tensions.
Huawei [HWT.UL] of China and Qualcomm are showcasing 5G products, while Samsung is offering a close-up look at a new $2,000 folding smartphone, the Galaxy Fold, that goes on sale in South Korea on Friday. Deutsche Telekom is marketing the Samsung Galaxy 5G and Galaxy Note 10+ 5G for early adopters, as well as the Huawei Mate 20X 5G and for home internet the HTC 5G Hub.
(Reporting by Douglas Busvine; Editing by Thomas Seythal and Jane Merriman)